Effect of Soil Test Based Fertilizer Application on Labile Soil Phosphorus Pool and Rice Grain Yield in Thanjavur District of Tamil Nadu (India)

The soil samples were collected and analyzed to find out the efficacy of soil test based fertilizer applications in rice using Mitscherlich-Bray (M&B) concept. The rice grain yield and labile soil phosphorus was estimated in four farmer's fields during kharif and rabi seasons at Kattuthottam village in Thanjavur district, Tamilnadu (India). The results showed that grain yield was at 75% sufficiency level and the yield targeting at 75% of theoretical maximum yield as per M&B concept was similar in these fields with varying fertility in both the seasons. The yield during kharif season was more as compared to rabi season since the latter falls in wet season leading to poor nutrient uptake. The labile P was less pronounced immediately after the harvest of kharif crop. However, it was higher at post-harvest stage of rabi crop which coincided with wet season in the year and seemed to have substantially released less soluble/stable P fractions to labile pool.